The hardest part of this is not the software. It is the empty page. Most people stall here, and the way out is to stop trying to write an About page.
Three sentences, in this order.
1. What you fix
Not your job title. The problem somebody has before they think of you.
"I find the reason a WordPress site is costing more to host than it should." "I fix checkouts that are losing orders." "I write the documentation nobody on your team has time to write."
If a stranger cannot tell from this sentence whether they have the problem, it is too abstract. "Full-stack developer" is a category, not a problem.
2. Who you fix it for
Narrow is better than broad. Somebody reading "I help small businesses" does not know if they count. Somebody reading "I help Shopify stores doing $50k a month or more" knows immediately.
You will feel like you are turning people away. You are — and the ones who stay are more certain they are in the right place.
3. What it costs and how to start
A price and a button. This is the sentence most people leave off, and it is the one that decides whether a stranger becomes a client this afternoon or thinks about it and forgets.
Then add the proof
Once those three are down, add whatever shows you can do it: a short piece about how you solved something, a two-minute video walking through your approach, a before and after. That material does more work than a portfolio grid, because it shows how you think rather than what you shipped.
You can add it later. Publish the three sentences today.